Vulcanization of rubber



Patented Dec. 18, 1945 UNITED STATES PATENT OFFICE VULIGANIZATION OF RUBBER Albert F. Hardman, Akron, Ohio, assignor to Wingfoot Corporation, Akron, Ohio, at COIPOIZl-v tion of Delaware No Drawing. Original application February 26,

1943, Serial No. 477,263. Divided and this application February 5, 195, Serial No. 576,371

2 Claims.

Example 1 A mixture of '72 grams of fi-naphthol, 90 grams of a 25% aqueous solution of dimethylamine, 53 grams of freshly distilled benzaldehyde and 100 cc. of ethyl alcohol was allowed to stand at room temperature for 2 days. Crystals began to separate after about 2 or 3 hours. The crystals were filtered off and washed with alcohol. The yield was 107 grams. The product melted at 156-l58 C. and corresponds to the structural formula err- H,

Example 2 Twenty-eight grams of l-(alpha-dimethylaminobenzyl) naphthol-2 (the product of Example 1), grams of carbon bisulfide and 100 cc. of ethyl alcohol were mixed and the mixture was-refluxed for 7 or 8 hours. The white crystals originally present did not dissolve immediate in the boiling solvent but slowly changed in appearance. The mixture was allowed to stand overnight and the crystals were then filtered off and washed with alcohol. After drying, the product weighed 35 grams and melted with decomposition at 167 C. The product is believed to conform to the following structural formula:

H Analysis showed a sulfur content of 18.03% and a nitrogen content of 3.60%. The theoretical sulfur and nitrogen contents based on the structural formula shown are 18.1% and 3.96%, respectively.

The product of Example 2 was compounded into rubber as an accelerator according to following Formula A and samples were cured and tested in the usual manner.

An excellent cure was obtained in 30 minutes at 240 F. with no tendency to scorch. The ultimate tensile strength was kg./sq. cm., the ultimate elongation was 755% and the modulus at 500% elongation was 32 kg./sq. cm.

The accelerator compound per se is claimed in my co-pending application Serial No. 477,263, filed February 26, 1943 of which the present application is a division.

I claim:

1. The method of treating rubber which comprises vulcanizing it in the presence of the ad-'- dition product of equimolecular proportions of carbon bisulfide and l-(a-dimethylaminobenzyl) naphthol-2.

2. A rubber product which has been vulcanized in the presence of the addition product of equimolecular proportions of carbon bisulfide and 1- (u-dimethylaminobenzyl) naphthol-Z.

ALBERT F. HARDMAN. 

